Perfluoroalkanesulfonyl fluorides are useful as starting materials for the preparation of a variety of useful compounds. For example, perfluoromethanesulfonyl fluoride can be used to prepare perfluoromethanesulfonic acid, which has been reported to be the strongest of all known monoprotic organic acids. (See R. D. Howells and J. D. McCown, Chem. Rev., 77, 69 (1977).) Perfluoroalkanesulfonyl fluorides can also be utilized to prepare perfluoroalkanesulfonamides (which are useful as herbicides, antimicrobials, and pharmaceuticals) and salts such as lithium perfluoroalkanesulfonates and lithium bis (perfluoroalkanesulfonyl)imides (which are useful as electrolyte salts for battery applications). (See P. J. Stang and M. R. White, Aldrichimica Acta, 16, 15 (1983) and Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Volume 3, page 1017, John Wiley & Sons, New York, (1992).)
Perfluoroalkanesulfonyl fluorides have been prepared from a variety of different starting materials by such methods as electrochemical fluorination, direct fluorination, and photolysis.
For example, U.S. Pat. No. 2,732,398 (Brice et al.) discloses the preparation of perfluoroalkanesulfonyl fluorides by the electrochemical fluorination (ECF) in anhydrous liquid hydrogen fluoride of the corresponding hydrocarbon alkanesulfonyl halides.
J. Fluorine Chem. 58, 326 (1992) (M. Novikova et al.) describes the preparation of perfluoromethanesulfonyl fluoride by direct gas-phase fluorination of (fluorosulfonyl)difluoroacetyl fluoride.
Syntheses, 972 (1979) (N. D. Volkov et al.) discloses the preparation of halodifluoromethanesulfonyl fluorides by photolysis of the corresponding 2-halo-2-oxodifluoroethanesulfonyl fluorides.